Similarity-based retrieval of images is an important task in many image database applications. Interactive similarity retrieval is one way to resolve the fuzzy area involving psychological and physiological factors of individuals during the retrieval process. A good interactive similarity system is not only dependent on a good measure system, but also closely related to the structure of the image database and the retrieval process based on the respective image database structure. In this paper, we propose to use a dynamic similarity measure on top of the enhanced digraph index structure for interactive iconic image similarity retrieval. Our approach makes use of the multiple feedbacks from the user to get the hidden subjective information during the retrieval process, and avoids the high cost of re-computation of an interactive retrieval algorithm. Copyright 2006 ACM.